Question

The product of two consecutive integers is 72. The equation x(x + 1) = 72 represents the situation, where x represents the smaller integer. Which equation can be factored and solved for the smaller integer?

x2 + x – 72 = 0
x2 + x + 72 = 0
x2 + 2x – 72 = 0
x2 + 2x + 72 = 0

Answer 1

x^2 + x - 72 = 0

Factor: (x + 9)(x - 8) = 0, so x = -9 or x = 8.
Thus the smaller integer is -9 (with -8) or 8 (with 9).